Interesting that "Sanus" is an anagram of Susan, but not a reversal --"nasuS". If it were a typesetter's error, I suppose I could see how the upper case "S" would obviously go first in the chase, when making up the forme, and then the rest... got scrambled. If they were using pre-cast two-letter increments --both "us" and "an" being useful words on their own-- it might have been a case of using an upper-case "S" and then swapping the next two type-pieces.